Fluid-cooled wall for double-fired furnaces



June 6, 1933. 1,912,880

FLUID COOLED WALL FOR DOUBLE-FIRED FURNACES J. 5. BENNETT 4 Sheets-Sheet 1 Filed May 15, 1931 Jpn 6, 1933. J. 5. BENNETT 1,912,830

FLUID COOLED WALL FOR DOUBLE-FIRED FURNACES Filed May 15, 1951 4 Sheets-Sheet 2 June 6, 1933. J. 5. BENNETT FLUID COOLED WALL FOR DOUBLE-FIRED FURNACES 4 SheetsSheet 3 Filed May 15, 1951 W 4/ m v Patented June 6, 1933 Q UNITED ST res aosnrrr s. BENNETT, or MERION, PENNSYLVANiA,fASSIGNOR T AMERICAN ENGINEER-,7

PATENT orrlcsme COMPANY. or PHILADELQKHIA, rENNsYLvANrA, A CORPORATION or PENNSYL- vA'NIA 1 FLUID-cOQL nWAL non A lication med 'mi s,

This invention relates to'improvements in tubular fluid-cooled walls of the type adapted for use in furnaces, retorts and the like for protection against excessively high temperatures and for the purpose of reducing clinker and slag adhes'ions-pr y In my copending application, SerMNo. 219,706, I have described' atubularz'fluidcooled Wall construction primarily adapted toinstallations of underfeedstokers of the type involving'an inclined combustion grate.

My present invention has to do with the application of this type of fluid-cooled wall to multiple-fired furnaces of the type including oppositely arrangedfstokers terminating 1n a common ash pit, and a principal object of the invention, therefore, is to provide in a multiple-fired furnace of the stated character a fluid-cooled wall having the desirable characteristicsand advantages ofthe: wall disclosed in my aforesaid copending application. I A

'The invention further-resides in certain novel and advantageous structural features and arrangements hereinafter described and illustrated in the attached drawings, in

which Figurevl is a diagrammatic sectional view of a double-fired furnace equipped with a fluid-cooled wall made in accordance with my invention Fig.2- is a diagrammatic sectional view of the fluid-cooled wallon' the line 22, 1;

Figs. 3 and 4 are, respectively, fragmentary horizontal sectional view and front elevation illustrating a modificationof my'invention; Y I 1 Figs. 5 and 6 are, respectively, fragmentary horizontal sectionaland front eleva-- tional views illustrating a further modification;

. 7 Figs. 7 and 8 are, respectively,fragmentary horizontal sectional and front elevationlal views 'illustratinga still: further modifica- Figs, li and 12 are, respectively, horizontal DOUBLE-FIRED FURNACES 1931. Serial missmez, I

sectionaland front elevational views illustrat-ing still another modification within. the scope of'the invention. 7; With reference to'the drawings, the-numerals 1, 1 designate the inclined converging combustion grates of the oppositely arranged stokers of a double-firedfurnace, said grates in a preferred form comprising alternately arranged tuyeres and retorts and terminating attheir lower ends in a common ash .pit 2. Each of said grates is provided with vthe usual mechanism 3 located externally of the oppositewalls 4, 4, of the furnaceifor feeding fuel to the upper ends of the various retorts and for operating the secondary fuelfeeding stoker elements (not shown) whereby the-fuel is advanced at a predetermined rate downwardly over the grates, andthe'ashes .and fuel refuse eventually deposited in the ash pit 2. In the present instance, the ash A pit is shown as-providedwith crusher rolls 5 which operate in well known manner to discharge the ashes from the bottom of the pit. In accordance with my invention, the op site side-walls 11 of the furnace are,pro

wardly on converging lines substantially paralleling the' in'clination-of' the said grates. Preferably these panels 12, '12 v are constructed in accordance with the principles set forth .in my aforesaid copendingeapplication; In accordance with these principlesgthe walls 11 in a. preferred embodiment are provided with inclined converging recesses corresponding in dimensions and positionwith the panels 12.

Within each of-these recesses is mounted a series of-tubes 13 arranged-in a flat bank extending longitudinally of the recess; The

"upper end of each 'ofthese banks of tubes is connected in the present instance to a header 14 located respectivelyin the walls 4:, and

at their lower ends the tubes of the respective banks terminate, in the present instance, in a common header 15 which, as shown in Fig. 2, is cylindrical in form and which is set in the wall at the juncture of the said recesses. The headers 14 and 15 may be connected in an independent fluid-circulating system or to the water system of the boiler of which the furnace may constitute a part.

Attached to each ofthe tubes 13 of both banks is a series of blocks 16 which collectively form a protective facing for the said banks of tubes and which constitute the inner effective wall surface of the panels 12, 12, said blocks neatly filling thesaid recesses wherebya continuous and preferably flush side wall is provided including the fluid-cooled panels 12 which, as illustrated, extend the full lengths of the grates 1, 1 in positions bounding the side edges of the latter.

While I prefer to construct this wall in ac cordance with the structural details set forth in my aforesaid copending application, it will in Figs. 3 and 4, the tubes 23, 23, of the respective converging panels, instead of terminating in a common header, are extended rearwardly beyond thejunction point 24 and are respectively connected to headers 25, 25 set in the side wall 26 of the furnace. In this instance also, the tubes of the respective panels may be connected to entirely independent fluid-circulating systems, or may be individually connected to the boiler system of the furnace. Blocks 27 are employed to form a protective facing over the tubes 23, said blocks including a series 28 overlying the junction of the lower ends of the tubes and forming with the adjacent surfaces of the 'wall 26 a continuous wall surface. In this instance also I have employed a suitable refractory cement 29 to seal the joints between adjacent blocks.

Referring to Fig. 4, it will be noted that the blocks 28 of the series overlying the j unction of theconverging tubes 23 are rectangular in form,as also are the blocks of an adj acent vertical series, whereas the remaining blocks 27 are of parallelepiped formwith their upper and lower edges inclined at an angle corresponding to the angle of inclination of the tubes 23. The arrangement affords ready means for covering the overlapping portions of the said tubes.

f In the embodiment shown in Figs. 5 and 6, the converging tubes 33, 33 terminate at their lower ends in a common header 34 after the manner previously described and illuscooled panel, and certain of these blocks designated generally by th'e'referencenumeral 37 are so formed as tofit the junction area of the two sets" of tubes and to overlie not only. the lower ends of the tubes but also the forward face of theheader 34. i

In that embodiment of my invention shown 7 in Figs. 7 and 8, the tubes 43 of the converging banks extend rearwardly at their lower ends to connect with a pair of .headers 44, 44, at the back of they wall. The rearward extensions of the lower ends of the tubes 43 he closely adjacenteach other, and the space therebetween is filled with a suitable refractory cement 45, the forward face of this mass 45 forming with the blocks 46 a continuous wall surface and a protectivefacing for the tubes 43.

The embodiment illustrated in Figs. 9 and 10 is similar to that illustrated in Figs. 7 and 8, with the difference that in the embodiment of Figs. 9 and 10, the ducts 53 of the respecive converging banks enter a single header 54 at their lower ends instead of the ind-ividual headers shown in the prior described embodiment. In this instance, the space at the forward side of the banks between the rearward extensions of the tubes is filled with a body of a suitable refractory cement 55, the usual protective blocks 56 being provided and forming with said cement 55 a continuous fluid-cooled wall surface for the furnace.

In the embodiments shown in Figs. 7 to 10, inclusive, and also in Fig. 3, I have rovided for expansion-and contraction oft e tubes due to temperature changes. The headers are I placed well behind the tubes and the terminal ends of the latter connecting with the headers extend rearwardly from the plane of the wall at an angle permitting expansion and contraction of the tubes with substantial free- .1

adjacent ends of the converging banks may be of such character as to permit the expansion of the tubes or maybe so supported as to provide the necessary clearances.

In that form of mydevice shown in Figs. 11 and 12, the tubes .63 of the respective banks are extended downwardly in parallel arrangement so as to embrace within the cooled area the side wall of the furnace ash pit 2 at the lower ends of the grates. In this instance, the tubes of both banks join, ahorizontal I header 64. I The effective su'r face ofthe fluidcooled panel in this'instance is formed entirely by the protective blocks 65, which are secured as a facing over the tubes 63 and which are carried down to the extreme lower ends of the tubes 63 where they join the header 64.

A further modification is illustrated in Figs. 13 and 14, in which the tubes 73 of the two banks connect at their lower ends to a pair of vertically arranged headers 74, 74. The forward sides of these headers are exposed on the effective wall surface of the panel, and the space therebetween is filled by a mass of suitable refractory cement 75. Cement is also used to fill in the spaces between the refractory blocks 7 6 forming the major portion of the protective facing and the spaces between the edges of the lowermost of these refractory blocks and the sides of the headers 74.

I claim: v

1. A furnace comprising oppositely arranged inclined and downwardly converging combustion grates terminating in a common ash pit, and tubular cooling means for the side walls of the furnace comprising inclined and downwardly converging banks of JOSEPH is. BENNETT.

tubes bounding the edges of said grates and extended at their lower ends to comprehend thesides of said ash pit within the cooled areas, and headers for said tubes at the upper ends of the said rates and adjacent the bottom of the said as pit.

2. A furnace comprising an bustion grate terminating in an ash pit, and a fluid-cooled panel bounding a side of said grate and comprising a plurality of tubes extending from the upper end of the grate to the bottom at an inclination correspondinclined coming substantially to that of the grate said tubes at their lower ends being deflected downwardly so as to embrace within the cooled area the side wall of said ash pit, and headers for said tubes located at the top of the combustion grate and adjacent the bottom of said pit.

3. A furnace comprising an inclined -com-' bustion grate terminating at its lower end in an ash pit, headers at the upperend of said grate and adjacent the bottom of the ash pitrespectively, and tubes connected with said headers and arranged to form a continuous fluid-cooled panel bounding the side of the combustion grate and embracing the side wall of said pit.

4. A furnace comprising an inclined com.-

- bustion grate terminating in an ash pit, and

a fluid-cooledpanel bounding a side of said grate and comprising a plurality of tubes extending from the upper end of the grate to the bottom at an inclination corresponding substantially to that of the grate, said tubes at their lower ends being deflected downwardly so as to embrace, within the cooled area the side wall of said ash pit, headers for said tubes located at the top of the 

